Nikon S3600 has a
20.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor . On the other hand, Canon A3500 IS has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features DIGIC 4 processor.
Below you can see the S3600 and A3500 IS sensor size comparison.
Nikon S3600 and Canon A3500 IS have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.